427 IR Crate Engine

427-IR Crate Engine * Image may contain optional upgrades.
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2 Year Limited
Horse Power
560 hp
Dynamometer Tested

Putting the "HOT" Into Hot Rods

Premium Crate Engines are for Street Rodders, Car Builders, and people looking for the thrill of ROUSH performance.

CONTACT: For more crate motors info, email us at roushengines@roush.com


  • 560 HP
  • 9.5 deck height
  • Small block
  • Iron 4-bolt block
  • Steel crank
  • H-beam rods
  • Forged pistons
  • Aluminum CNC ported heads
  • Roller cam
  • 8-stack intake
  • Electric Fuel Injection
  • Dynamometer tested
  • Premium fuel
  • Turn-key ready
  • 2-year / 24,000-mile limited warranty
  • Recommended for use with manual transmissions

Technical Specifications

  • Engine Family: SBF
  • Displacement: 427 cid
  • Power: 560 hp
  • Torque: 540 ft-lbf
  • Cylinder Block: 9.500" Iron
  • Crankshaft Type: Steel
  • Crankshaft Stroke: 4.000 in
  • Piston Type: Forged Aluminum
  • Conrod Type: Steel H-Beam
  • Timing Chain: Double Roller
  • Lifter: Hydraulic Roller
  • Cylinder Head: Aluminum
  • Intake Port: CNC
  • Intake Manifold Material: Aluminum
  • Intake Manifold Config: 8-Stack
  • Fueling: EFI
  • Fuel Grade: Premium Gasoline
  • Oil Weight: 10W-30
  • Max Engine Speed: 6250 rpm
  • Limited Warranty: 2 Years / 24,000 Miles
  • EFI Instruction Manual: (Download)
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.

Crate Engine Characteristics

ROUSH Crate Engines are high-performance engines that are based on and operate like the engines designed and produced in the 1960s and later. However, unlike engines of that time, ROUSH Crate Engines (like other crate engines currently manufactured in the marketplace) produce significantly more power and torque. As a consequence of this, these engines have characteristics different from the original production engines upon which they have been based. The following characteristics are not covered by the ROUSH Crate Engine Limited Warranty and should be considered before purchase.

Additionally, It will be the sole responsibility of the installer/end user to select components and optimize the vehicle system based on each vehicle's unique characteristics, and it's intended use. This includes, but is not limited to the selection and/or optimization of the vehicle cooling system, air flow adequacy, A/C system performance, etc., and the suitability of the vehicle and its systems for the end use and environment (weather conditions, altitude, etc.).

Specifically ROUSH Crate Engines:

  • Are assembled with larger operating clearances
  • Will likely have a rougher idle due to the high performance camshaft design
  • Will likely make more mechanical noise
  • Will likely consume more oil during normal operation
  • Will generate more heat due to the increased power level
  • May exhibit non-production-like drive characteristics at various speeds and load conditions
  • Will likely consume more fuel due to the increased power level
  • Will produce +/- 2% of the advertised power
  • May, as configured by an installer or end user, only be legally used in emissions-exempt applications.

40 Years and Counting

The storied history of ROUSH Performance began over 40 years ago with the founding of Jack Roush Performance Engineering, and we’re still growing.